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<?xml version="1.0"?>
<!--
Licensed to the Apache Software Foundation (ASF) under one or more
contributor license agreements. See the NOTICE file distributed with
this work for additional information regarding copyright ownership.
The ASF licenses this file to You under the Apache License, Version 2.0
(the "License"); you may not use this file except in compliance with
the License. You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
-->
<!DOCTYPE document [
<!ENTITY project SYSTEM "project.xml">
]>
<document url="default-servlet.html">
&project;
<properties>
<author email="funkman@apache.org">Tim Funk</author>
<title>Default Servlet Reference</title>
</properties>
<body>
<section name="Table of Contents">
<toc/>
</section>
<section anchor="what" name="What is the DefaultServlet">
<p>
The default servlet is the servlet which serves static resources as well
as serves the directory listings (if directory listings are enabled).
</p>
</section>
<section anchor="where" name="Where is it declared?">
<p>
It is declared globally in <i>$CATALINA_BASE/conf/web.xml</i>.
By default here is it's declaration:
</p>
<source><![CDATA[ <servlet>
<servlet-name>default</servlet-name>
<servlet-class>
org.apache.catalina.servlets.DefaultServlet
</servlet-class>
<init-param>
<param-name>debug</param-name>
<param-value>0</param-value>
</init-param>
<init-param>
<param-name>listings</param-name>
<param-value>false</param-value>
</init-param>
<load-on-startup>1</load-on-startup>
</servlet>
...
<servlet-mapping>
<servlet-name>default</servlet-name>
<url-pattern>/</url-pattern>
</servlet-mapping>]]></source>
So by default, the default servlet is loaded at webapp startup and
directory listings are disabled and debugging is turned off.
</section>
<section anchor="change" name="What can I change?">
<p>
The DefaultServlet allows the following initParamters:
</p>
<properties>
<property name="debug">
Debugging level. It is not very useful unless you are a tomcat
developer. As
of this writing, useful values are 0, 1, 11, 1000. [0]
</property>
<property name="listings">
If no welcome file is present, can a directory listing be
shown?
value may be <b>true</b> or <b>false</b> [false]
<br />
Welcome files are part of the servlet api.
<br />
<b>WARNING:</b> Listings of directories containing many entries are
expensive. Multiple requests for large directory listings can consume
significant proportions of server resources.
</property>
<property name="readmeFile">
If a directory listing is presented, a readme file may also
be presented with the listing. This file is inserted as is
so it may contain HTML.
</property>
<property name="globalXsltFile">
If you wish to customize your directory listing, you
can use an XSL transformation. This value is a relative file name (to
either $CATALINA_BASE/conf/ or $CATALINA_HOME/conf/) which will be used
for all directory listings. This can be overridden per context and/or
per directory. See <strong>contextXsltFile</strong> and
<strong>localXsltFile</strong> below. The format of the xml is shown
below.
</property>
<property name="contextXsltFile">
You may also customize your directory listing by context by
configuring <code>contextXsltFile</code>. This must be a context
relative path (e.g.: <code>/path/to/context.xslt</code>) to a file with
a <code>.xsl</code> or <code>.xslt</code> extension. This overrides
<code>globalXsltFile</code>. If this value is present but a file does
not exist, then <code>globalXsltFile</code> will be used. If
<code>globalXsltFile</code> does not exist, then the default
directory listing will be shown.
</property>
<property name="localXsltFile">
You may also customize your directory listing by directory by
configuring <code>localXsltFile</code>. This must be a file in the
directory where the listing will take place to with a
<code>.xsl</code> or <code>.xslt</code> extension. This overrides
<code>globalXsltFile</code> and <code>contextXsltFile</code>. If this
value is present but a file does not exist, then
<code>contextXsltFile</code> will be used. If
<code>contextXsltFile</code> does not exist, then
<code>globalXsltFile</code> will be used. If
<code>globalXsltFile</code> does not exist, then the default
directory listing will be shown.
</property>
<property name="input">
Input buffer size (in bytes) when reading
resources to be served. [2048]
</property>
<property name="output">
Output buffer size (in bytes) when writing
resources to be served. [2048]
</property>
<property name="readonly">
Is this context "read only", so HTTP commands like PUT and
DELETE are rejected? [true]
</property>
<property name="fileEncoding">
File encoding to be used when reading static resources.
[platform default]
</property>
<property name="sendfileSize">
If the connector used supports sendfile, this represents the minimal
file size in KB for which sendfile will be used. Use a negative value
to always disable sendfile. [48]
</property>
<property name="useAcceptRanges">
If true, the Accept-Ranges header will be set when appropriate for the
response. [true]
</property>
<property name="showServerInfo">
Should server information be presented in the response sent to clients
when directory listing is enabled. [true]
</property>
</properties>
</section>
<section anchor="dir" name="How do I customize directory listings?">
<p>You can override DefaultServlet with you own implementation and use that
in your web.xml declaration. If you
can understand what was just said, we will assume you can read the code
to DefaultServlet servlet and make the appropriate adjustments. (If not,
then that method isn't for you)
</p>
<p>
You can use either <code>localXsltFile</code> or
<code>globalXsltFile</code> and DefaultServlet will create
an xml document and run it through an xsl transformation based
on the values provided in <code>localXsltFile</code> and
<code>globalXsltFile</code>. <code>localXsltFile</code> is first
checked, followed by <code>globalXsltFile</code>, then default
behaviors takes place.
</p>
<p>
Format:
</p>
<source><![CDATA[ <listing>
<entries>
<entry type='file|dir' urlPath='aPath' size='###' date='gmt date'>
fileName1
</entry>
<entry type='file|dir' urlPath='aPath' size='###' date='gmt date'>
fileName2
</entry>
...
</entries>
<readme></readme>
</listing>]]></source>
<ul>
<li>size will be missing if <code>type='dir'</code></li>
<li>Readme is a CDATA entry</li>
</ul>
<p>
The following is a sample xsl file which mimics the default tomcat behavior:
</p>
<source><![CDATA[<?xml version="1.0" encoding="UTF-8"?>
<xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
version="3.0">
<xsl:output method="html" html-version="5.0"
encoding="UTF-8" indent="no"
doctype-system="about:legacy-compat"/>
<xsl:template match="listing">
<html>
<head>
<title>
Sample Directory Listing For
<xsl:value-of select="@directory"/>
</title>
<style>
h1 {color : white;background-color : #0086b2;}
h3 {color : white;background-color : #0086b2;}
body {font-family : sans-serif,Arial,Tahoma;
color : black;background-color : white;}
b {color : white;background-color : #0086b2;}
a {color : black;} HR{color : #0086b2;}
table td { padding: 5px; }
</style>
</head>
<body>
<h1>Sample Directory Listing For
<xsl:value-of select="@directory"/>
</h1>
<hr style="height: 1px;" />
<table style="width: 100%;">
<tr>
<th style="text-align: left;">Filename</th>
<th style="text-align: center;">Size</th>
<th style="text-align: right;">Last Modified</th>
</tr>
<xsl:apply-templates select="entries"/>
</table>
<xsl:apply-templates select="readme"/>
<hr style="height: 1px;" />
<h3>Apache Tomcat/8.0</h3>
</body>
</html>
</xsl:template>
<xsl:template match="entries">
<xsl:apply-templates select="entry"/>
</xsl:template>
<xsl:template match="readme">
<hr style="height: 1px;" />
<pre><xsl:apply-templates/></pre>
</xsl:template>
<xsl:template match="entry">
<tr>
<td style="text-align: left;">
<xsl:variable name="urlPath" select="@urlPath"/>
<a href="{$urlPath}">
<pre><xsl:apply-templates/></pre>
</a>
</td>
<td style="text-align: right;">
<pre><xsl:value-of select="@size"/></pre>
</td>
<td style="text-align: right;">
<pre><xsl:value-of select="@date"/></pre>
</td>
</tr>
</xsl:template>
</xsl:stylesheet>]]></source>
</section>
<section anchor="secure" name="How do I secure directory listings?">
Use web.xml in each individual webapp. See the security section of the
Servlet specification.
</section>
</body>
</document>
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